Change the following line
cmd.Parameters.Add("@Aname", SqlDbType.VarChar) = aname ;
to
cmd.Parameters.Add("@Aname", SqlDbType.VarChar);
cmd.Parameters["@Aname"].Value = aname;
(or)
cmd.Parameters.Add("@Aname", SqlDbType.VarChar).Value = aname;
First you have to add the parameter and specify the type of parameter and then assign a value to that parameter.
Refer this link
http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.parameters.aspx[
^] for more information.